Web-based scoring of the dicentric assay, a collaborative biodosimetric scoring strategy for population triage in large scale radiation accidents

Abstract

In the case of a large scale radiation accident high throughput methods of biological dosimetry for population triage are needed to identify individuals requiring clinical treatment. The dicentric assay performed in web-based scoring mode may be a very suitable technique. Within the MULTIBIODOSE EU FP7 project a network is being established of 8 laboratories with expertise in dose estimations based on the dicentric assay. Here, the manual dicentric assay was tested in a web-based scoring mode. More than 23,000 high resolution images of metaphase spreads (only first mitosis) were captured by four laboratories and established as image galleries on the internet (cloud). The galleries included images of a complete dose effect curve (0-5.0 Gy) and three types of irradiation scenarios simulating acute whole body, partial body and protracted exposure. The blood samples had been irradiated in vitro with gamma rays at the University of Ghent, Belgium. Two laboratories provided image galleries from Fluorescence plus Giemsa stained slides (3 h colcemid) and the image galleries from the other two laboratories contained images from Giemsa stained preparations (24 h colcemid). Each of the 8 participating laboratories analysed 3 dose points of the dose effect curve (scoring 100 cells for each point) and 3 unknown dose points (50 cells) for each of the 3 simulated irradiation scenarios. At first all analyses were performed in a QuickScan Mode without scoring individual chromosomes, followed by conventional scoring (only complete cells, 46 centromeres). The calibration curves obtained using these two scoring methods were very similar, with no significant difference in the linear-quadratic curve coefficients. Analysis of variance showed a significant effect of dose on the yield of dicentrics, but no significant effect of the laboratories, different methods of slide preparation or different incubation times used for colcemid. The results obtained to date within the MULTIBIODOSE project by a network of 8 collaborating laboratories throughout Europe are very promising. The dicentric assay in the web based scoring mode as a high throughput scoring strategy is a useful application for biodosimetry in the case of a large scale radiation accident.

Biodosimetry versus physical dosimetry for emergency dose assessment following large-scale radiological exposures

“…There are published intercomparisons for: (1) EPR using ex-vivo teeth (Wieser et al, 2005); (2) DCA analysis for blood lymphocytes (Wilkins et al, 2008Livingston et al, 2011;Romm et al, 2014); (3) EPR analysis of screen glass from mobile phones ; and (4) OSL from surface mount resistors (SMRs) from mobile phones (Bassinet et al, 2014). What we lack entirely is an intercomparison between biodosimetry methods and physical dosimetry methods in the same study.…”

“…Thus, person-specific sensitivity of the chosen biomarker to the radiation becomes a potential issue. This appears to be a minor problem for dosimetry with DCA (Romm et al, 2014), but may be more of an issue for dose assessment using other biodosimetry techniques (Coleman, 2015).…”

“…Example details are described elsewhere (e.g. Wilkins et al, 2008;Romm et al, 2012Romm et al, , 2014. The calibration procedure generates a calibration curve for that lab, specific to the reference radiation type and energy.…”

“…In the EPR studies (Wieser et al, 2005;Fattibene et al, 2014) and the OSL studies (Bassinet et al, 2014) is it stipulated that the dose is given in terms of air kerma. For DCA (Wilkins et al, 2008;Romm et al, 2014) the dose is dose to water. It is assumed that the doses evaluated by the individual laboratories are also quoted in terms of the same reference.…”

EPRBioDose 2013: EPR applications and biological dosimetry

“…However, dose evaluation can be accelerated by the automation of the methods for cytogenetic analysis as was demonstrated by Rodrigues et al (2014). In order to evaluate possibilities to increase laboratory capacities in DC scoring, experiences within a network for web-based scoring of images from metaphase spreads were reported by Romm et al (2014).…”